Construction and Evaluation of Recombinant Strains for Ethanol Production from Lignocellulosic Hydrolysate

2011 ◽  
Vol 347-353 ◽  
pp. 48-51 ◽  
Author(s):  
Shao Lan Zou ◽  
Chao Zhang ◽  
Yuan Yuan Ma ◽  
Le You ◽  
Min Hua Zhang
Keyword(s):  
Carbon Source ◽  
Ethanol Production ◽  
Rapid Growth ◽  
Sole Carbon Source ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Corn Straw ◽  
Lignocellulosic Hydrolysate ◽  
Preliminary Results ◽  
Theoretical Yield

The recombinant Z.mobilis CX was constructed. Its ethanol concentration and ethanol yield from 2% xylose at 36 h were 6.73 g/L and 82.3% of theoretical yield, respectively. The recombinant S.cerevisiae YB was constructed and was showed to utilize cellobiose as the sole carbon source for rapid growth and ethanol production. The maximum ethanol concentration 7.493 g/L and ethanol yield 77.4% of theoretical yield from 2% cellobiose were obtained at 24 h. Further, the preliminary results of SSF of pretreated corn straw demonstrated the potential of improving ethanol production and reducing the costs of cellose enzymes used by co-fermentation of CX and YB.

scholarly journals Hemicellulosic Bioethanol Production from Fast-Growing Paulownia Biomass

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 173
Author(s):  
Elena Domínguez ◽  
Pablo G. del Río ◽  
Aloia Romaní ◽  
Gil Garrote ◽  
Lucília Domingues
Keyword(s):  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Xylose Reductase ◽  
Energy Crop ◽  
Scheffersomyces Stipitis ◽  
Fractionation Process ◽  
Renewable Source ◽  
Fast Growing ◽  
Engineered Strain

In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.

Fuel Ethanol Production from Wet Oxidised Corn Stover by S. Cerevisiae

2011 ◽  
Vol 343-344 ◽  
pp. 963-967 ◽  
Author(s):  
Zhang Qiang ◽  
Anne Belinda Thomsen
Keyword(s):  
Ethanol Production ◽  
Corn Stover ◽  
Simultaneous Saccharification And Fermentation ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Liquid Fraction ◽  
Raw Material ◽  
Wet Oxidation ◽  
Inhibition Effect ◽  
Simultaneous Saccharification

In order to find out appropriate process for ethanol production from corn stover, wet oxidation（195°C，15 minutes）and simultaneous saccharification and fermentation (SSF) was carried out to produce ethanol. The results showed that the cellulose recovery of 92.9% and the hemicellulose recovery of 74.6% were obtained after pretreatment. 86.5% of cellulose was remained in the solid cake . After 24h hydrolysis at 50°C using cellulase（Cellubrix L）,the achieved conversion of cellulose to glucose was 64.8%. Ethanol production was evaluated from dried solid cake and the hydrolysate was employed as liquid fraction . After 142 h of SSF with substrate concentration of 8% (W/V), ethanol yield of 73.1 % of the theoretical based on glucose in the raw material was obtained by S. cerevisiae(ordinary baker’ yeast) . The corresponding ethanol concentration and volumetric productivity were 17.2g/L and 0.121g/L.h respectively. The estimated total ethanol production was 257.7 kg/ton raw material by assuming consumption of both C-6 and C-5. No obvious inhibition effect occurred during SSF. These instructions give you the basic guidelines for preparing papers for WCICA/IEEE conference proceedings.

scholarly journals Medium optimization for ethanol production with Clostridium autoethanogenum with carbon monoxide as sole carbon source

2010 ◽  
Vol 101 (22) ◽  
pp. 8784-8789 ◽  
Author(s):  
Ying Guo ◽  
Jingliang Xu ◽  
Yu Zhang ◽  
Huijuan Xu ◽  
Zhenhong Yuan ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Carbon Source ◽  
Ethanol Production ◽  
Sole Carbon Source ◽  
Medium Optimization ◽  
Clostridium Autoethanogenum

scholarly journals Ethanol Production from Nondetoxified Dilute-Acid Lignocellulosic Hydrolysate by Cocultures of Saccharomyces cerevisiae Y5 and Pichia stipitis CBS6054

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ping Wan ◽  
Dongmei Zhai ◽  
Zhen Wang ◽  
Xiushan Yang ◽  
Shen Tian
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Synthetic Medium ◽  
Pichia Stipitis ◽  
Dilute Acid ◽  
Acid Hydrolysate ◽  
Issatchenkia Orientalis ◽  
Final Ethanol Concentration

Saccharomyces cerevisiae Y5 (CGMCC no. 2660) and Issatchenkia orientalis Y4 (CGMCC no. 2159) were combined individually with Pichia stipitis CBS6054 to establish the cocultures of Y5 + CBS6054 and Y4 + CBS6054. The coculture Y5 + CBS6054 effectively metabolized furfural and HMF and converted xylose and glucose mixture to ethanol with ethanol concentration of 16.6 g/L and ethanol yield of 0.46 g ethanol/g sugar, corresponding to 91.2% of the maximal theoretical value in synthetic medium. Accordingly, the nondetoxified dilute-acid hydrolysate was used to produce ethanol by co-culture Y5 + CBS6054. The co-culture consumed glucose along with furfural and HMF completely in 12 h, and all xylose within 96 h, resulting in a final ethanol concentration of 27.4 g/L and ethanol yield of 0.43 g ethanol/g sugar, corresponding to 85.1% of the maximal theoretical value. The results indicated that the co-culture of Y5 + CBS6054 was a satisfying combination for ethanol production from non-detoxified dilute-acid lignocellulosic hydrolysates. This co-culture showed a promising prospect for industrial application.

Construction of Yeast Strain Capable of Co-Fermenting Pentose and Hexose by Protoplast Fusion

2013 ◽  
Vol 781-784 ◽  
pp. 847-851
Author(s):  
Jin Ling Guo ◽  
Da Chun Gong ◽  
Zhi Jun Li ◽  
Zhou Zheng
Keyword(s):  
Ethanol Production ◽  
Protoplast Fusion ◽  
Genetic Stability ◽  
Parental Strain ◽  
Conversion Rate ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Production Capacity ◽  
Pachysolen Tannophilus ◽  
Alcohol Conversion

Saccharomyces cerevisiae R40 and Pachysolen tannophilus P01 were used as the parental strain to construct an engineering strain capable of co-fermenting pentose and hexose by protoplast fusion. A fusant F202 was obtained through inactivating parental protoplasts, screening with YPX solid medium and high glucose liquid medium, ethanol production capacity detecting and identification with PCR-SSR technique. Subsequently, the fermentation performance and genetic stability of F202 was studied. The maximum ethanol production capacity from glucose was 1.47 ml/100 ml with a sugar and alcohol conversion rate 47% which was 11% higher than the parental strain P01. By fermenting xylose the ethanol concentration could achieve to 0.58 ml/100 ml with a sugar and alcohol conversion rate 12%. An ethanol concentration of 1.2 ml/100 ml was obtained by fermenting the mixture of xylose and glucose (mass ratio 1:2). Moreover, no decrease in ethanol yield after 8 generations propagation suggested fustant 202 possessed good genetic stability.

Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium

2011 ◽  
Vol 64 (2) ◽  
pp. 341-347 ◽  
Author(s):  
Ana F. Tomas ◽  
Dimitar Karakashev ◽  
Irini Angelidaki
Keyword(s):  
Production Process ◽  
Ethanol Production ◽  
Yeast Extract ◽  
Ethanol Yield ◽  
Thermophilic Bacterium ◽  
Promising Candidate ◽  
Theoretical Yield ◽  
Ethanol Yields ◽  
Nutrients Concentration ◽  
Xylose Concentration

An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixed culture, originally isolated from a hydrogen producing reactor operated at 70 °C. Ethanol yields were assessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to grow without nutrient addition (yeast extract, peptone and vitamins) was also assessed. The maximum ethanol yield achieved was 1.28 molethanol/molxylose consumed (77% of the theoretical yield), at 2 g/l of initial xylose concentration. The isolate was able to grow and produce ethanol as the main fermentation product under most of the conditions tested, including in media lacking vitamins, peptone and yeast extract. The results indicate that this new organism is a promising candidate for the development of a second generation bio-ethanol production process.

scholarly journals Microwave-assisted hydrotropic pretreatment as a new and highly efficient way to cellulosic ethanol production from maize distillery stillage

2021 ◽  
Author(s):  
Mikulski Dawid ◽  
Kłosowski Grzegorz
Keyword(s):  
Ethanol Production ◽  
Cellulosic Ethanol ◽  
Enzymatic Degradation ◽  
Ethanol Concentration ◽  
Process Conditions ◽  
Fermentation Inhibitors ◽  
Microwave Assisted ◽  
Theoretical Yield ◽  
High Level ◽  
Very High

Abstract Aim of the study was to assess the suitability of the combined use of microwave radiation and sodium cumene sulfonate under optimized process conditions for the preparation of maize stillage biomass as a raw material for the production of cellulosic ethanol. The key parameter guaranteeing a high level of lignin removal from biomass (ca. 44%) was concentration of hydrotrope. Even at high biomass concentration (16% w/v) and a cellulase enzyme dose of about 4 filter-paper units/g, maize stillage biomass subjected to microwave-assisted hydrotropic pretreatment was highly susceptible to enzymatic degradation, which resulted in 80% hydrolysis yield. It is possible to obtain a fermentation medium with a very high glucose concentration (up to 80 g/L), without fermentation inhibitors and, as a consequence, to reach a very high level of sugar conversion to ethanol (concentration above 40 g/L), even as much as 95% of theoretical yield. Microwave hydrotropic treatment with sodium cumene sulfonate is a very effective way to prepare waste maize stillage biomass for the production of cellulosic ethanol. The degradation of the lignocellulose structure by the simultaneous use of microwaves and hydrotropes ensured a high degree of conversion of structural polysaccharides to bioethanol. The method provides a high level of enzymatic degradation of cellulose, leading to a medium with high content of released sugars suitable for bioconversion, which is in line with assumptions of the second-generation ethanol production technology. Key points • Microwave-assisted hydrotropic pretreatment is a new way to cellulosic ethanol production. • Microwave-assisted hydrotropic delignification removes 44% of lignin from biomass. • No fermentation inhibitors are obtained after microwave-assisted hydrotropic pretreatment. • High ethanol concentration (above 40 g/L) and fermentation yield (95% of theoretical yield) from biomass after microwave-assisted hydrotropic pretreatment.

scholarly journals Metabolic Engineering of Zymomonas moblis for Ethylene Production

2019 ◽  
Author(s):  
Yan He ◽  
Bo Wu ◽  
Wei Xia ◽  
Kun-Yang Zhao ◽  
Qiong Tan ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Carbon Source ◽  
Ethylene Production ◽  
Sole Carbon Source ◽  
High Stress ◽  
Cellulosic Biomass ◽  
Corn Straw ◽  
Enzymatic Hydrolysate ◽  
Alternative Approach ◽  
Engineering Work

Abstract Background: Biological ethylene production via the ethylene-forming enzyme (EFE) can offer a promising sustainable alternative approach for fossil-based ethylene production. The high stress tolerance of Z. mobilis make it as promising bio-ethylene producer.Results: In this study, Heterologous expression of the efe gene in Z. mobilis successfully converted the non-ethylene producing strain into an ethylene producer. What’s more, we systematically performed the effect of knocking out the competitive metabolic pathway of pyruvate and the addition of nutrients to the medium to improve the ethylene production in Z. mobilis. These optimization pathways and different substrate supplies resulted in higher ethylene productivity (from 1.36 to 12.83 nmol/OD600/ml), which may guide future engineering work on ethylene production in other organisms to further improve ethylene productivity. Meanwhile, we obtained ethylene production of 5.8 nmol/OD600/ml in strain ZM532-efe by using enzymatic hydrolysate of corn straw as the sole carbon source. This is also the first report on the production of ethylene from cellulosic biomass.Conclusions: These results indicate that the engineered Z. mobilis show great potential for production of ethylene from cellulosic biomass in the future.

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